Some simulations also analyze physiological measures including metabolism, energy expenditure, and fatigue limits Cycle time studies, design and process validation, user comfort, reachability, and line of sight are other human-factors that may be examined in ergonomic simulation packages.
12.
Provided that load limits were observed, the idea of a'fatigue limit'entered bearing lifetime calculations : if the bearing was not loaded beyond this limit, its theoretical lifetime would be limited only by external factors, such as contamination or a failure of lubrication.
13.
Where \ sigma _ \ text { a } is the alternating stress, \ sigma _ \ text { m } is the mean stress, \ sigma _ \ text { fat } is the fatigue limit for completely reversed loading, and \ sigma _ \ text { ts } is the ultimate tensile strength of the material.
